How to make a Fabric modded Minecraft server (2026)
How to make a Fabric modded Minecraft server in 2026: Java 25, the Fabric server launcher, eula.txt, port 25565, RAM and which mods the server needs.
Published 6 min readby the Synagy team, written with AI
Short answer: to make a Fabric modded Minecraft server, install Java 25, download the Fabric server launcher for your version, start it once, set eula=true and drop the same mods your players use into the mods folder. A small server wants at least 2 GB of RAM, and friends connect on port 25565. The steps below work the same on Windows, macOS and Linux.
This guide uses Minecraft: Java Edition 26.3 as the example, but the steps are the same for 26.2 and 1.21.1. Only the Java version and the mod files change.
What do you need before you start?
You need four things. Check them first, because most failed servers break on one of these:
- Java 25. The Minecraft Wiki page for Java Edition 26.3 lists Java SE 25 as the minimum. Version 26.3 came out on September 15, 2026. The Fabric wiki server guide lists Java 21 for 1.20.5 and newer, so 1.21.1 runs on Java 21.
- A computer that stays on. Your own PC works for a weekend with friends. For a server that runs all day, rent a host.
- At least 2 GB of free RAM. That is the minimum the Minecraft Wiki server tutorial gives for small servers. Big modpacks need more.
- The mod files. Every mod must match the server version and the loader. A Fabric 26.3 mod will not load on 26.2 or on NeoForge.
If you have not installed Fabric on your own game yet, read our guide on how to install Fabric mods on Minecraft 26.3 first. Your players need the same setup.
How do you set up a Fabric server, step by step?
The Fabric server launcher does most of the work. It is one .jar file that downloads Minecraft and Fabric Loader the first time it runs.
- Make a folderone empty folder only for the server
- Get the launcherpick your Minecraft and Loader version on fabricmc.net
- Start it onceit downloads the game files, then stops
- Accept the EULAchange eula=false to eula=true
- Add mods and restartsame versions your players use
- Make a folder. Create a new folder, for example
fabric-server. Everything the server writes will land here. - Download the launcher. Open the Fabric server download page. Pick your Minecraft version, the latest stable Loader and the latest Installer. Save the file into your folder.
- Start it once. Use the launch command the Fabric page shows you. The first start needs internet, because it fetches the Minecraft server files.
- Accept the EULA. The first run creates a file called
eula.txt. Open it and changeeula=falsetoeula=true. Without this, the server stops right away. - Add mods and restart. Put your mod
.jarfiles into the newmodsfolder. Most mods also need Fabric API, so add that too. Then start the server again.
A typical command looks like java -Xms1024M -Xmx2048M -jar fabric-server.jar nogui. The -Xmx value is the most RAM the server may use. Raise it to 4096M or more for larger modpacks.
Which mods go on the server, and which stay on the client?
Content mods go on both sides. Visual mods stay on the client only. The rule is simple: if a mod adds blocks, items, mobs or recipes, the server and every player need the exact same file.
| Mod type | Server | Player's game |
|---|---|---|
| New blocks, items, mobs, biomes | Yes | Yes, same version |
| Fabric API | Yes | Yes |
| Server tools (backups, permissions) | Yes | No |
| Shaders, minimaps, performance for graphics | No | Yes |
| Resource packs | Optional | Yes |
Modrinth shows on every mod page whether it runs on the client, the server or both. Check that label before you copy a mod over. A pure graphics mod on a server can crash it on start.
The easiest way to keep players in sync is a modpack. Build it once, share it, and everyone gets the same files. Our guide on how to make a Minecraft modpack shows how to export one.
How do your friends join the server?
On the same network, friends join with your PC's local IP address. Over the internet, you need port forwarding or a host. Minecraft uses port 25565 by default, and you can change it in server.properties.
For play over the internet, you have two common options:
- Port forwarding. Open port 25565 in your firewall. Then add a rule on your router that sends it to your PC's local IP. Friends join with your public IP address.
- A server host. Many hosts install Fabric with one click and keep the server running when your PC is off. You pay a monthly fee, and you skip the router setup.
server.properties also holds the basics: world name, game mode, difficulty and the maximum number of players. Change them while the server is stopped, then start it again.
Can you run your own mod on the server?
Yes. A Fabric mod you made yourself is a normal .jar file, so it goes into the mods folder like any other mod. The only rule is the same as always: server and players need the same version.
With Synagy for Minecraft, you describe a mod in plain words inside the game and watch it being built. Every part passes a compile, generated game tests and a 60 second crash test on a headless dedicated server before it counts as done. The result is a .jar with full source code, built for Minecraft 26.2 with Fabric.
Where Synagy stops matters here. Mods are built and played on 26.2. The free Mod Compiler can also build a finished mod for Fabric 26.3, Fabric 1.21.1 and NeoForge 26.2, tested on a real server of that version. Synagy makes no server plugins for Paper or Spigot, and Bedrock is not supported. Synagy is in a free beta right now, with 25 Free Credits a day. Planned plans are on the pricing page.
FAQ
Do I need Fabric API on a Fabric server?
Almost always, yes. The Fabric download page says most mods need Fabric API in the mods folder. Put the same Fabric API version on the server and on every player's game, matched to your Minecraft version.
How much RAM does a modded Minecraft server need?
The Minecraft Wiki recommends at least 2 GB for a small server. A modded server with many content mods usually needs more. Start with 4 GB for a handful of friends and raise the -Xmx value if the server lags.
Why does my Fabric server stop right after it starts?
The most common reason is the EULA. Open eula.txt and set eula=true. Other causes are the wrong Java version, such as Java 21 on Minecraft 26.3, or a client-only mod in the server's mods folder.
Can Bedrock players join a Fabric server?
Not on their own. A Fabric server runs Java Edition, and Bedrock players use a different game. Some servers add bridge software for Bedrock players, but those tools are separate projects and not part of Fabric.
Written with AI and checked automatically before publishing, without a human editor. Spotted a mistake? Tell us and we fix it.
